Adsorption of gas phase methyl radicals on the oxygen modified Mo(100) single crystal surface

Mimicking Aspects of Heterogeneous Catalysis: Generating, Isolating, and Reacting Proposed Surface Intermediates on Single Crystals in Vacuum

“…28 Ethane and methane are secondary reaction products. [28][29][30][31] The significant aspect for most surface experiments is that the products besides methyl radicals are species which do not readily adsorb. Thus, when the flux from this source is impinged onto surfaces held at 100 K, methane, ethane, and nitrogen generally desorb while methyls are trapped intact.…”

“…In the first surface application of this source, methyl radicals were adsorbed onto an oxygen-covered Mo(100) surface. 29 Subsequently, methyls have been adsorbed, isolated, and identified on Cu(111), 30 Cu(100), 33 Pt(111), 31 Ni(100), 34 and Rh (111). 32 It should also be noted that CH 3 radicals have been produced for surface studies by passing methane over a partial oxidation catalyst (Li x Mg x O).…”

“…For radicals, source purity is particularly critical because of the difficulty in filtering neutral particles. In the case of methyl radicals, a simple and highly effective source based on the gas phase pyrolysis of azomethane has been developed 28 and is finding considerable application in surface studies. − The concept behind the azomethane source as developed by Stair and co-workers 28 is illustrated schematically in Figure . As shown, azomethane is passed into the vacuum system through a tube whose terminus is heated to ∼1000 K. Gas-phase unimolecular decomposition produces methyl radicals and nitrogen .…”

“…As shown, azomethane is passed into the vacuum system through a tube whose terminus is heated to ∼1000 K. Gas-phase unimolecular decomposition produces methyl radicals and nitrogen . Ethane and methane are secondary reaction products. − The significant aspect for most surface experiments is that the products besides methyl radicals are species which do not readily adsorb. Thus, when the flux from this source is impinged onto surfaces held at 100 K, methane, ethane, and nitrogen generally desorb while methyls are trapped intact.…”

“…Thus, when the flux from this source is impinged onto surfaces held at 100 K, methane, ethane, and nitrogen generally desorb while methyls are trapped intact. In the first surface application of this source, methyl radicals were adsorbed onto an oxygen-covered Mo(100) surface Cu(100), Pt(111), Ni(100), and Rh(111) .…”